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===== Simulation with FPadSim =====

In many cases, HepSim detector simulations were done using ILCSOFT-derived software.
To create full simulations, you will need to convert ProMC files  to LCIO files. This is described in
[[hepsim:usage_truth#converting_to_lcio|LCIO conversions]] and [[hepsim:dev_full|LCIO]] sections.

Many samples posted in HepSim are created with the  package called "fpadsim" (**F**uture **Pa**rticle **D**etector **Sim**ulator"). This package is under constant development. 
)


The package includes packages from ilcsoft, such as SLIC, PandoraPFA, and LCSIM
The simulation and reconstruction proceeds as: SLIC->LCSIM->slicPandora/PandoraPFA.
This digram shows the entire chain:

{{:hepsim:fpdasim_reco.png?700|}}


The input for SLIC are LCIO files with truth-level information ("MCParticle" table). The files
are created from ProMC files using the converter promc2lcio (included inside
the ProMC packages, in the directory "examples").
This concept originates from the SiD detector(T.Johnson, N.Graf, J.McCormick, J.Strube),
and later was re-purposed to be used for generic feature detectors, including
proton pp colliders (S.Chekanov, A.Kotwal). The final step
of the reconstruction is PandoraPFA (J.Marshall, M.Thomson).

====== Simulations with FPadSim ======

To process truth-level events with FpadSim, you need a few things:

  * A tag file with the detector description. The concept of tag files is described in Sect.[[hepsim:dev_tags]]. You can find all submitted tag files in [[http://atlaswww.hep.anl.gov/hepsim/recotags.php|tag file catalog]]
  * Singularity  container with pre-built libraries to process a given tag file

The tag files should be processed with the simulation and reconstruction chain described above.
This can be done by using [[http://singularity.lbl.gov/|Singularity]] that enables users to have full control of their environment. Install singularity (version 2.3.1 and above) and download the CentOS7 HEPSIM image with the  FPadSim software.

Here is the download link [[http://atlaswww.hep.anl.gov/hepsim/soft/centos7hepsim.img|centos7hepsim.img]] (>5 GB).
The image includes basic CentOS7 environment, and programs such as SLIC, LCSIM, slicPandora, ProMC, Jas4PP, ROOT, PYTHIA8, LHAPDF  and various converters.

<code bash>
wget http://atlaswww.hep.anl.gov/hepsim/soft/centos7hepsim.img # get the singularity image
singularity  exec centos7hepsim.img  bash -l                   # setup fpadsim
</code>
After the last line, the environment should be ready. For example, type "slic -h". It shows the available commands. 

Now you can process the tag file:

<code bash>
wget http://atlaswww.hep.anl.gov/hepsim/soft/rfull102.tgz
tar -zvxf rfull102.tgz
cd ilcsoft/rfull102/
./TEST.sh #  runs simple a test with single particles
</code>
The final file after pandoraPFA reconstruction with the name *hepsim.slcio" will be created in the same directory.
Other files after simulation and track reconstruction steps will be located inside "output" directory.

To process other promc files, download the required promc files and edit the file Test.sh

More information about how to use HepSim container can be found in Section [[hepsim:dev_singularity|HepSim singularity container]].

===== Light version of FPadSim image=====

David Blyth created a much lighter version of FPadSim image for EIC work described in Sec.[[fcs:eic:singularity|singularity image for EIC]]. It is based on Arch Linux, and does not contain the usual Linux environment included inside centos7hepsim image.


====== Contributions ======

The contributed authors of this package since 2015 are:

  * D.Blyth (HEP/ANL)
  * J.MacCormick (SLAC)
  * W.Armstrong  (PHYS/HEP)
  * S.Chekanov (HEP/ANL)
  * A.Kotwal (Duke)
  * J.Strube (PNNL)
  * J.Marshall (U.Cambridge)

 --- //[[chekanov@anl.gov|Sergei Chekanov]] 2017/04/12 21:58//